This invention relates to a torque transmitting system for transmitting torque in a drivetrain from a rotating driving shaft, at the output of an internal combustion engine, to a driven shaft, at the input of a manual transmission, without transferring torque fluctuations in the driving shaft, thereby precluding the development of torsional vibrations in the drivetrain that may otherwise be caused by the torque fluctuations.
The driving torque, produced by the output driving shaft (namely, the crankshaft) of an internal combustion engine, fluctuates or pulsates due to the operation of the pistons in the engine. Such a pulsating torque becomes more pronounced as modifications are made in internal combustion engines to permit those engines to operate at lower rotational speeds (RPM's), to achieve greater fuel economy, but yet at higher torque levels to maintain horsepower ratings. The higher torque levels require that each piston in the engine contribute a larger force each time its cylinder fires. The power produced by each stroke of the engine must be greater. These larger forces from the pistons are transmitted to the crankshaft, resulting in substantial torque fluctuations in the engine crankshaft output. Each time a cylinder fires, the torque sharply varies or fluctuates. The pulsating torque can resonate in the drivetrain creating torsional vibrations that may cause significant problems, such as reduced lifetimes for gears, bearings, shafts, splines, universal joints, differentials, etc.
Torsional dampener systems have been developed in the past for reducing torsional vibrations in drivetrains having manual transmissions, such as in trucks, but all of these prior systems have certain disadvantages, for example, high cost, large space requirements, complexity of construction, unreliability, inefficiency, and short operating life. In contrast, the torsional vibration dampening system of the present invention exhibits none of these disadvantages and instead provides a unique system of relatively simple and inexpensive construction, requiring no significant space, having a long lifetime, and being highly reliable and efficient in operation.